1. Field of the Invention
This invention relates to a printer sharing control technique for causing a computer to make print spool files and send the print spool files to a printer in response to print requests received from a plurality of printer use programs.
2. Description of the Related Art
The printer sharing control technique is a technique for allowing a plurality of computers connected through a network to share a printer on the network. In general, the printer is connected to a computer called a printer server which stores a program for effecting a printer sharing control. On the other hand, computers called clients each store an application for using the printer, i.e. a printer use program, for sending print requests. The printer server temporarily stores, in predetermined units as print spool files, print data received from the printer use programs, and successively sends the print spool files to the printer. Where the computer acting as the printer server has a higher performance than just executing this printer sharing control, the printer use program may be installed also on the printer server. Thus, the printer server may act also as a client to share the printer.
The temporary storage of the print spool files basically is controlled on a FIFO (First In First Out) basis, in which a print spool file inputted earlier is sent out earlier. To accommodate an urgent print output from a particular client, the server has also a function for allowing such client to access its printer sharing function and forcibly change an order in which the print spools are stored. However, print outputs from the printer will be in confusion when printing priorities are frequently changed by the clients without permission. The type of data processing may vary among the plurality of clients sharing the printer. For example, one client may engage in a real-time processing, while another does a batch processing. In such a case, it is undesirable to allow the clients to change the priorities of print outputs freely.